The invention relates to loudspeakers and more particularly to bending wave panel-form loudspeakers, e.g. of the general kind described in International patent application WO97/09842.
The technology described in International patent application WO97/09842 and its U.S. counterpart application No. 08/707,012, filed Sep. 3, 1996 (the latter being incorporated herein by reference in its entirety) has come to be known as distributed mode or DM technology and among other things, these applications describe a ceiling tile/loudspeaker combination. A feature of bending wave panel-form loudspeakers is that they may be made flat and of shallow depth and may thus be wall or ceiling mounted in a domestic, or other, environment to occupy a minimum of space. It has also been suggested that the flat front face of the loudspeaker may be disguised as a picture or mural.
It is an object of the invention to extend the utility of such wall or other surface mounting of panel-form loudspeakers for other purposes, by combining such loudspeakers with other devices in synergistic combinations.
According to the invention, there is provided a panel-form loudspeaker comprising a bending wave panel having a front face and rear face, a vibration exciter mounted to the panel to excite bending-wave vibration in the panel, and a light emitter mounted at or adjacent to the rear face of the panel and arranged to illuminate an area adjacent to the panel. A light reflector may be provided to direct light from the light emitter. The panel may be transparent or translucent.
The loudspeaker may comprise an enclosure defining a cavity enclosing at least a portion of the rear face of the panel. The light-emitter may be disposed in the cavity and may be arranged to emit light through at least one window therein. The enclosure may be transparent or translucent to light. The enclosure may be moulded from a clear plastic such as polycarbonate. The enclosure may be formed with one or more lenses to direct the emitted light as desired. The lens(es) may be moulded integrally with the enclosure.
The enclosure is preferably acoustically opaque to prevent or reduce acoustic radiation from the rear face of the panel. The cavity may be dimensioned such as to modify the modal behaviour of the member, e.g. as taught in W099/52322 and U.S. Pat. No. 08/707,012.
The light emitter may comprise a fluorescent device, or other device which does not emit significant heat. Such a device may be a low voltage device. Power to the light emitter may be supplied via electrically conductive lead(s) supplying power to the vibration exciter.
The loudspeaker may further comprise a front cover. The front cover will be acoustically transparent to allow acoustic radiation from the panel to pass through. The front cover is preferably opaque to light. The front cover may be arranged to extend beyond the panel perimeter and the enclosure. The loudspeaker may be adapted to be wall mounted or to be ceiling mounted, e.g. as a ceiling tile. Thus, when so mounted, the front cover may at least partly conceal the loudspeaker enclosure from view.